Analysis of Bogie Frame Manufactured with Different Processes

Transcription

1 Analysis of Bogie Frame Manufactured with Different Processes Subhankar Haldar #1 and Ravikant Verma *2 # Research Scholar, GD-Rungta College of Engineering & Technology, Bhilai, Chhattisgarh, INDIA * Assistant Professor, Department of Mechanical Engineering, GD-Rungta College of Engineering & Technology, Bhilai, Chhattisgarh, INDIA. Abstract This paper presents the analysis of bogie frame when manufactured through casting and fabrication by finite element method. The objective is to analyze effects of manufacturing over strength of the bogie frame with all its loading conditions. This is will provide us the best suited process of manufacturing for Bogie Frame. Keywords Bogie Frame, Casting, Fabrication, Finite Element Analysis, I. INTRODUCTION The HTSC (high traction/speed-three axle) bogie assembly support the weight of the locomotive and provide the means for transmission of power to the rails. The HTSC series truck is applied to AC transmission locomotives used in freight service. This bogie is designed as a powered bolster-less unit. The locomotive carbody weight is transferred directly to the bogie frame through four rubber secondary spring pad assemblies, which also provide yaw stiffness for tracking stability. The relatively stiff secondary suspension and uniform traction motor orientation improve weight transfer within the bogie for optimal adhesion performance. A soft primary suspension is designed to provide good ride quality and equalization of wheel set loads for operation over track irregularities. Traction loads are transmitted from the bogie to the locomotive under frame through the pivot pin assembly Although the bogie frame itself is rigid, the soft spring design allows the end axles yaw freedom within the frame to position the wheelset axles to the curves center for reduced wheel and rail wear. A traction rod and collar/bushing attached to the journal bearing adapters and bogie frame helps control movement of the end axles and transfers driving force to the bogie frame [1]. In the development of bogie frame, the design improvement of railway vehicle was done continuously to strengthen its strength and make up for its weakness [2]. In order to save energy and material, analysis of bogie is performed for various loading conditions by B H Park, K Y Lee [3]. Various studies including the constructional study of locomotive has been carried out to have information about the dynamic properties of the bogie [4]. WANG Kun-quanv analyzes the existing status and development of heavy haul traffic in various countries, and necessity and feasibility of development on heavy load AC locomotive bogie [5]. Geoffrey Boothroyd says during design is the initial step and the important decisions are made that affect the final cost of a product in this stage and also he focuses on the occurrence manufacturing problems in the early stages of product design and development[6]. Therefore, Bogie frame can be manufactured either through Casting Process (fig. I) or Fabrication (fig. II). Both the process gives different results when carried out. Fig. I Casting Bogie frame Fig. II Fabricated Bogie frame Masahiko Onosato says Virtual Manufacturing makes it possible to estimate manufacturing processes previously without using real facilities, and therefore, Virtual Manufacturing is expected to be used for many applications in manufacturing [7]. Hence finite element analysis of the bogie frame manufactured through the process of casting and fabrication should be done to check the results. The main objective is to check the results of both the processes and then compare them so that the bogie produced either of the processes with best results. ISSN: Page 22

2 II. CASTING AND FABRICATED BOGIE FRAME DETAILS HTSC bogie frame can be manufactured through Sand Casting Process. In this process the material selected for process is Cast Steel. The chemical composition is stated in Table I. Carbon,% Phosphorus,% Sulphur,% Carbon Equivalent, % TABLE I CHEMICAL COMPOSITION OF CAST STEEL The mechanical properties of Cast Steel used in the Casting process are stated in Table II. TABLE II MECHANICAL PROPERTIES OF CAST STEEL Now HTSC bogie when manufactured through Fabrication Process uses the following types of Material: Plates: E350 C Tubes: HFW Tube 0.25 max 0.85 max 0.05 max 0.06 max 0.40 max Tensile Strength, MPA, min 435 Yield Point, MPA, min 248 Elongation at 50mm gauge 24 length, %, min Reduction of Area, %, min 36 Hardness, Brinell The of E 350 C is briefly described in Table III and the chemical compositions Carbon, % 0.20 max 1.55 max Phosphorus, % max Sulphur, % max Silicon, % 0.45 max Carbon Equivalent, % 0.45 max of HFW Tube are shown in Table IV. TABLE III CHEMICAL COMPOSITION OF E 350 C TABLE IV CHEMICAL COMPOSITION OF HFW TUBE Now, the mechanical properties of the material E 350 C and HFW tube required for the analysis are tabulated in Table V and TableVI. TABLE V MECHANICAL PROPERTIES OF E 350 C TABLE VI MECHANICAL PROPERTIES OF HFW TUBE All the above properties are verified during mechanical testing. For mechanical testing of Cast steel, the test bar are to be cast integrally and heat treated by casting and all its properties should confirm to Truck Frame and Bolster Cast steel[8]. Similarly the properties of material for fabrication process confirms to IS: 2062 [9] and IS: 3601[10]. III. Carbon,% 0.20 max 1.30 max Phosphorus,% 0.04 max Sulphur,% 0.04 max Carbon Equivalent, % 0.45 max Tensile Strength, MPA, min 490 Yield Point, MPA, min 350 Elongation at gauge length s 0, %, min Internal Bend Diameter 2t Tensile Strength, MPA, min 430 Yield Point, MPA, min 275 Elongation at gauge length s 0, %, min Internal Bend Diameter 3t EVALUATION OF STRENGTH OF BOGIE FRAMES A. Structural integrity of Bogie frames The evaluation of strength for bogie frame was performed as per the assembly load details of locomotive. The static structural analysis of the bogie frame was done using Ansys v14.0 Workbench, a finite element analysis program. Fig. III shows the geometric model used for structural integrity analysis of bogie frame (casting model). ISSN: Page 23

3 Fig. III Solid Modelling of Casting Bogie Frame Fig. IV shows the FE model used for structural integrity analysis of bogie frame (fabricated model). Fig. VI Supports and Load Details of Fabricated Bogie Frame B. Strength of Bogie frames In order to evaluate the strength of bogie frame, stress results of static analysis were used. Fig VII and Fig VIII show the stress results of Casting Bogie Frame. Fig. IV Solid Modelling of Fabricated Bogie frame For finite element analysis the properties of Cast Steel for Casting Bogie and E 350 C and HFW tube for fabricated bogie are fed into Engineering material Section. During pre processing stage i.e., before meshing the materials are assigned to their respective models and parts. Fig. VII Stress Results of Casting Model After meshing the nodes and elements in the Casting model are and respectively whereas the nodes and elements in the fabricated model are and respectively. Now the equivalent stress and total deformation is analyzed with load of 125 T equally distributed over four parts and fixing the parts where wheel and axle assembly is fixed. Fig. V and Fig. VI shows the casting and fabricated bogie frame model with the loads and fixing supports. Fig. VIII Stress Results of Casting Model Above results show that the casting model produces maximum stress results which are not acceptable. Fig. V Supports and Load Details of Casting Bogie Frame Apart from this Fig. IX and Fig. X shows the deformation due the maximum stress developed. In the above figures the red spotted areas are showing the areas where the load of 125 T is equally distributed where as the blue spotted areas are showing the fixed supports. ISSN: Page 24

4 Fig. IX Deformation due to Stresses Developed. The above results shows that the maximum stresses developed are below the yield stress of the material hence the model developed is safe. Also, the Total Deformation shown in Fig. XIII and Fig. XIV at maximum stress developed are acceptable. Fig. XIII Deformation due to Stresses Developed. Fig. X Deformation Result due to Stress Developed This maximum deflection produced is 104 mm which is not acceptable. Now, the stress result for the fabricated bogie is shown in fig. XI and fig. XII. Fig. XIV Deformation Result due to Stress Developed. IV. RESULT AND DISCUSSION Fig. XI Stress Results of Fabricated Model All the above results show that manufacturing process plays a very important role in deciding the strength of the product. Apart from this there are some differences in both the processes: The weight of the casting Bogie is 6.5 T whereas the weight of fabricated model is 5.5 T which shows fabrication model is lighter than casting model. The chances of defects in the casting process are more than fabrication. The Defects arises in casting cannot be easily rectified or sometimes the product gets rejected due to its defects. Preparation of model through casting is a time taking process whereas the fabrication of the same product can be completed in multiple steps and in less time. Fig. XII Stress Results of Fabricated Model All these factors also make fabrication process more suitable than the casting process. ISSN: Page 25

5 V. CONCLUSION The structural integrity of a Fabricated Model of HTSC Bogie frame has produced the better results than the casting bogie frame under external loading conditions. Also the benefits of fabricated bogie frame are more. Hence fabricated bogie frame should be preferred over casting bogie frame. REFERENCES [7]. Masahiko Onosato, Development of a Virtual Manufacturing System by Integrating Product Models and Factory Models. CIRP Annals - Manufacturing Technology Volume 42, Issue 1, 1993, Pages [8]. Truck Frame and Bolster Cast steel Material, Specification by RDSO, EMS 22. [9]. Hot Rolled Medium and High Tensile Structural Steel. [MTD 4: Wrought Steel Products], Specification, IS 2062, [10]. Steel tubes for mechanical and general engineering purposes [MTD 19: Steel Tubes, Pipes and Fittings], Specification, IS 3601, [1]. Bogie Designs, Railway Technical Handbook [2]. K. B. Shin, D. H. Koo, S. H. Han. A study on material selection of the car body structure of Korean Tilting Train express (TTX) through the verification of design requirements. Korean society for railway, 2004, Vol.7, No.2, pp [3]. B H Park, K Y Lee, Bogie frame design in consideration of fatigue strength and weight reduction Journal of Rail and Rapid Transit, Published May 1, 2006 [4]. Sergey Myamlin, Mukolaj Luchanin, Larysa Neduzha. Construction analysis of mechanical parts of locomotives.the Dniepropetrovsk National University of Railway Transport named after Academician V. Lazaryan, 2, Lazarian St., Dnepropetrovsk-10, 49700, Ukraine, July [5]. WANG Kun-quan, Discussion of Bogie Scheme for 32t Axle-load AC Locomotive. Railway Locomotive & Car, 2011 [6]. Geoffrey Boothroyd, Product design for manufacture and assembly, University of Rhode Island, Kingston, RI 02881, USA, 28 February ISSN: Page 26